Safari won't open YouTube in Mojave and Catalina - what's wrong?

Question

YouTube

Three days ago, Safari stopped opening YouTube links from search engines (Google, Yandex). By clicking on such links, it simply gives out white pages. If you go directly to the address: youtube.com - the resource works fine!
I have an iMac 27 2017 Catalina. Today I demolished the system, and did a "clean installation" of Mojave - the problem did not go away ...
In Google Chrome, there is no such trouble ...
Tell me, what could be the reason?

Answer 1

Clearing cookies did not help ((
Safari -> Settings -> Privacy -> Manage website data
The problem turned out to be that all glitches with YouTube occur when I log in to it. As soon as I log out, everything works fine. Some kind of nonsense , I have never had such a headache in 8 years of working with a poppy ...
Here is another problem. I have a MacBook 2010 with High Sierra on board - the same problem! You can’t go to an authorized YouTube using a link from a search engine, or from WhatsApp .. .

Answer 2

I had the same problem, and it just kind of happened all of a sudden. It helped me in the settings to give permission to the Flash Player to turn on You Tube. Apparently, with the next update, all settings were reset to a ban. I have Catalina 10.15.6